Gate design with plunging nozzle and a waste reservoir for separating off ratio material

ABSTRACT

This invention relates generally to an apparatus for casting a portion of a tire or other article of manufacture, and, more specifically, to an apparatus that has a gate design, that has a plunging nozzle with a waste reservoir for separating off-ratio material before it enters the cavity that forms a portion of the tire or other article of manufacture. The design may further include a passage that connects the runner to the waste reservoir as-well as an air vent that allows trapped gas or air to exit the waste reservoir as it fills with waste material, a valve that is operative!&#39;/associated with the passage for closing and opening the passage at appropriate times, and a nozzle constructed from two independently translating components for initially introducing material into the waste reservoir and subsequently into the runner.

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates generally to an apparatus for casting a portionof a tire or other article of manufacture, and, more specifically, to anapparatus that has a gate design that has a plunging nozzle with a wastereservoir for separating off-ratio material before it enters the cavitythat forms a portion of the tire or other article of manufacture. Thedesign may further include a passage that connects the runner to thewaste reservoir as well as an air vent that allows trapped gas or air toexit the waste reservoir as it fills with waste material, a valve thatis operatively associated with the passage for closing and opening thepassage at appropriate times, and a two piece nozzle for initiallyintroducing material into the waste reservoir and subsequently into therunner.

Description of the Related Art

An emerging field in tire development involves the manufacture and useof non-pneumatic or hybrid tires that do not depend solely on gas tosupport the tire structurally as these tires are not prone to deflation,which can render standard pneumatic tires inoperable. An example of sucha tire is disclosed by U.S. Pat. No. 7,201,194, which is commonly ownedby the applicant of the present application. The content of this patentis incorporated herein by reference for all purposes in its entirety. Inan exemplary embodiment of the '194 patent, the non-pneumatic tireincludes an outer annular shear band and a plurality of web spokes thatextend transversely across and radially inward from the annular shearband and are anchored in a wheel or hub. In certain embodiments, theannular shear band may further comprise a shear layer, at least a firstmembrane adhered to the radially inward extent of the shear layer and atleast a second membrane adhered to the radially outward extent of theshear layer. In addition to the ability to operate without a requiredinflation pressure, the invention of U.S. Pat. No. 7,201,194 alsoprovides advantages that include a more uniform ground contact pressurethroughout the length of the contact area. Hence, this tire mimics theperformance of a pneumatic tire.

FIG. 1 shows such a tire that defines a radial direction R. Forreference, all the reference numerals in the 100's used herein refer tothe features while ail reference numerals in the 200's used herein referto a molding apparatus for making such a tire and reference numerals inthe 300's used herein refer to features of a gate, runner and wastereservoir design according to a first embodiment of the presentinvention and reference numerals in the 400's used herein refer to afeatures of a second embodiment of the present invention. The tire 100comprises a tread 102 that is attached to the outward extent 104 of thespokes 106, which in turn, are connected to a hub or wheel 108 at theirinward extent 110 by means known in the art such as by molding spokesbetween the hub 108 and the tread 102, which have been prepared forsuitable bonding to the polyurethane. An outer annular band 105 islocated between the outward extent of the spokes and the tread and aninner annular band 107 is found at the inward extent of the spokes,connecting them together. This inner annular band 107 can be used toattach the tire to a hub or wheel.

For the version of the tire 100 shown, the annular bands 105, 107 andspokes 106 are formed by pouring a polyurethane liquid into a rotationalmold where the liquid is spread via centrifugation and then cured orhardened (see published patent application WO 2012094005 A1 for anexample). It can also be seen that the spokes 106 are grouped in pairsand that the individual spokes 106′, 106″ within each pair areconsistently spaced from each other and that each pair is spacedconsistently from the adjacent pair around the circumference of thetire. The spacing within each pair and the spacing between each adjacentpair do not need to be the same. As described by the Abstract and col.2, lines 28-41 of the '194 patent, the spokes 106 support the tire 100in tension near the top of the tire 100 and not in compression. Instead,the spokes 106 at the bottom of the tire near the contact patch, whichis where the tread 102 of the tire 100 contacts the road, compress orbuckle easily. This helps the tire to simulate the pneumatic supportfunction of a pneumatic tire.

Due to the sensitive and important function that the annular bands 105,107 serve, i.e., to create the bond between the tread and the hub orwheel, as well as aesthetic concerns, it is desirable that the thicknessof the bands remain constant. Looking at FIG. 2, mold cores 238″ foundon a bottom mold half 234 are shown that form the spokes and insidesurfaces 101 of the annular bands. These mold cores are drafted on thesurfaces 237 that form the spokes themselves as mold cores coming fromone side of the mold interarticulate with similarly configured moldcores coming from the other half so that the thickness of the spokes canremain constant even if there is draft present. However, these moldcores are undrafted on the surfaces 235 that form the inside surfaces ofthe annular bands. In the case of the inside surface of the outerannular band 105, the inside surface of the tread is substantiallycylindrical, requiring that the inside surface of the outer annular bandalso be cylindrical to maintain the thickness of the annular band and toavoid aesthetic inconsistencies on the outer annular baud from one sideof the tire to the other. A similar situation exists for the insideannular band.

Due to the structural requirements of the spokes and the annular bands,it is preferable that they be formed without bubbles, sinks, voids, orother molding or casting defects as these can deleteriously affect theperformance of the tire. Also, it is desirable that the quality of thepolyurethane that forms these portions of the tire be good so that oncecured, these structures do not fail when the tire is used. In otherwords, the tire's spoke structure and annular bands require that all thepolyurethane used in these areas meets minimum properties. Polyurethanedispensed from most commercially available machines or mixheads todayinherently output initially some amount of poor quality or off-ratiomaterial for a short period of time at the beginning of the shot. Thisresults in the initial part of the shot being discarded. Typically, thisis done by dispensing the material into a separate container outside ofthe mold and then while dispensing, moving the injection nozzle backover the mold cavity, which can be messy.

Additionally, when using low pressure mixheads, as the mixhead is movedafter dispensing a shot, there is a problem with dripping polyurethaneas the mixhead moves away from the mold. This happens since thesemixheads have nozzles that are gravity fed and that lack a shutoffvalve. In applications where there is some type of valve associated withthe mixhead that is used for filling the mold, such as when a ball valveis employed, the flow is momentarily stopped or dead headed, resultingin disruption in the flow, which causes metering inaccuracy of thedispensing machine. That is to say, the ratio of material components isundesirably impacted and thus inaccurate.

Yet another problem with using commercially available injection systemsis that when the gate is below the final level of polyurethane, as isthe case when a bottom fill scheme is used, there is a need to preventbackflow from the mold cavity through the gate and back through the feedsystem.

Accordingly, it is desirable to find an apparatus and method that allowssuch tires or other articles of manufacture to be made using a feedsystem that allows polyurethane or other material to be fed into a moldcavity after the poor quality material has been separated and discardedwithout necessitating movement of the mixhead, dripping of the materialor any other type of mess. It would be particularly useful if such anapparatus and method could be designed that prevented backflow throughthe gate after the mold cavity has been filled. Finally, it would beideal if the proposed apparatus and method could be used with rotationalor non-rotational casting or molding.

SUMMARY OF THE INVENTION

Particular embodiments of the present invention include an apparatus formolding or casting an article of manufacture that has a mold cavity anda feed system for filling the mold cavity with a fluid material. Thefeed system may have structural members that define a series of voidsincluding a waste reservoir, a runner, a passage that connects the wastereservoir to the runner, allowing fluid communication between the wastereservoir and the runner. An injection point may also be provided forintroducing fluid into the waste reservoir as well as a gate thatprovides fluid communication between the runner and the mold cavity. Thefeed system further includes a plunging nozzle that defines a plungeaxis along which the nozzle is configured to plunge. The relativeplacements of the voids along the plunge axis are such that the wastereservoir may be immediately adjacent the injection point along theplunge axis, the passage is fluffier away from the injection point thanthe waste reservoir and is immediately adjacent the waste reservoiralong the plunge axis, the runner is further away from the injectionpoint than the passage and is immediately adjacent to the passage alongthe plunge axis, and the gate is further away from the injection pointand is immediately adjacent the runner along the plunge axis and themold cavity is furthest away from the injection point than any othervoid. In most cases, the injection point houses the injection nozzlehaving a plunge axis.

In some oases, an air vent is in fluid communication with the wastereservoir and may include as shut off valve. Likewise, there may be ashut off valve that is operatively associated with the passage foropening and closing the passage.

In other embodiments, the waste reservoir has a volume, the runner has avolume, the passage has a volume and the mold cavity has a volume andthe passage has a smaller void volume than the runner or wastereservoir. In some cases, the void volume of the waste reservoir isgreater than the void volume of the passage or the runner.

In further embodiments, the runner and gate have annular configurationsboth of which rotate about a central axis. In some cases, these annularconfigurations make complete 360 degree revolutions about the centralaxis. Similarly, the waste reservoir may also have an annularconfiguration that rotates about a central axis and it may make a 360degree rotation about the central axis. The central axis for the gate,runner and waste reservoir may be the same for all three voids and maycoincide with the plunge axis of the nozzle.

In many embodiments, the injection nozzle comprises two pieces includingan inner member and an outer sleeve, which are independently capable oftranslating relative to each other. In some cases, the pieces of thenozzle are attached to each other with the stem of the inner memberextending through the top surface of the right elbow portion of theouter sleeve.

Particular embodiments of the present invention include method formanufacturing an article comprising the step of providing an apparatuswith structural members that define voids including a mold cavity and afeed system. The feed system may include an injection point, wastereservoir, a runner, a passage that connects the waste reservoir to therunner, and a gate that connects the runner to the mold cavity. Themethod may further comprise the steps of injecting fluid material intothe waste reservoir and then stopping the filling of the wastereservoir, in some cases, this happens before it is completely filled. Acontrol system that is capable of receiving, processing and sendingsignals may also be provided. Signals may be sent to the control systemby sensors, which generate the signals after certain events haveoccurred, and signals may be sent by the control system to valves forcontrolling their opening and closing. In some embodiments, the relativeplacement of the injection point, waste reservoir, passage, runner, gateand mold cavity occur along the plunge axis. This may occur in any orderbut preferably in the order just mentioned.

In certain embodiments, the method may further comprise the step ofproviding fluid communication between the waste reservoir and the runnerbefore the waste reservoir has been completely filled. In manyinstances, the reservoir will have been mostly filled. A signal may bethen sent to a valve associated with the air vent that is incommunication with the waste reservoir for closing the valve. About thesame time, the valve associated with the passage may be opened to createfluid communication between the waste reservoir and the runner. In somecases, the valve to the passage is opened before the valve to the airvent is closed to help prevent flow hesitation.

In other embodiments, the method may further comprise the step of movingat least a portion of the nozzle to a position along the plunge axiswhere the nozzle begins filling the waste reservoir. The method mayfurther comprise a step of moving at least a portion of the nozzle toanother position along the plunge axis where the nozzle begins fillingthe passage and runner. In such a case, the method may further comprisethe step of providing a shut off valve, which is operatively associatedwith the passage for opening and closing the passage.

In certain embodiments, the step of providing the nozzle includesproviding the nozzle with a two piece construction including an outersleeve and an inner member that are capable of translating relative toeach other. The method may further comprise the step of opening thevalve that is operatively associated with the passage for allowing fluidcommunication between the waste reservoir and the runner.

In some cases, the step of moving at least a portion of the nozzle tofill the waste reservoir includes moving the outer sleeve. In otherscenarios, the step of moving at least a portion of the nozzle to fillthe passage and runner includes moving the inner member of the nozzle.It may further include providing a shut off valve with a ramped valvemember and/or a membrane.

Similarly in other embodiments, the method may further comprise the stepof generating a signal that indicates when the mold cavity is filled.Then, the valve associated with the passage may be shut off to preventflow back from the mold cavity into the gate and the feed system ingeneral. Also, a shut off nozzle may be provided that is housed orplaced into the injection point. This nozzle may be shut off after thevalve associated with the passage has been closed. Then the fluidmaterial found in the molding cavity for making the article as well asthe material found in the feed system may be hardened and cured.Finally, the hardened or cured article or hardened or cured feed systemmay be removed from the apparatus.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more detailed descriptionsof particular embodiments of the invention, as illustrated in theaccompanying drawing wherein like reference numbers represent like partsof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a non-pneumatic tire that has spokesthat can be molded using an apparatus according to an embodiment of thepresent invention;

FIG. 2 is a perspective view of a mold half and associated cores thatform the spokes of the tire of FIG. 1;

FIG. 3 is a perspective view of a testing apparatus employing a methodand apparatus according to a first embodiment of the present invention;

FIG. 4 is an enlarged sectional view of the waste reservoir, runner andgate of the first embodiment of the present invention taken along lines4-4 of FIG. 3, showing the flow of material from the runner through thegate into the mold cavity;

FIG. 5 is perspective view taken from FIG. 4 with only the shut offvalve assembly that closes the passage connecting the waste reservoir tothe runner and gate that is defined by the upper and lower members shownfor clarity;

FIG. 6 is an enlarged view of FIG. 5 showing the passage connecting thewaste reservoir to the runner and the passage valve shutting off on aridge or gasket more clearly;

FIG. 7 is a perspective view of the upper member of FIG. 5 showing therunner and fan shaped passage that are machined on it;

FIG. 8 is a perspective view of the lower member of FIG. 5 showing thewaste reservoir and gasket channels machined on it;

FIG. 9 is an enlarged sectional view of the upper and lower membersshowing the gate defined by these members in more detail;

FIG. 10 is a partial sectional view of the first embodiment of thepresent invention taken along a radial plane of the testing apparatusshowing the filling of the waste reservoir until bad material has beenpurged from the injection apparatus;

FIG. 11 is the partial sectional view of FIG. 10 after the air vent thatis in fluid communication with the waste reservoir has been closed,causing a hydrostatic buildup of pressure that causes material to flowinto the passage and pass its shut off valve that has been opened,allowing the runner, gate and mold cavity to fill with materialsequentially;

FIG. 12 is an sectional view of a second embodiment of the presentinvention that uses a plunging nozzle and a diaphragm like valve:

FIG. 13 shows the nozzle of FIG. 12 in a configuration and position thatallows the filling of the waste reservoir with poor quality material;

FIG. 14 shows the nozzle of FIG. 12 in a configuration and position thatallows the filling of the waste reservoir and passage, runner, gate andmold cavity with good quality material;

FIG. 15 shows the nozzle of FIG. 12 in a configuration and position thatshuts off the filling of the waste reservoir and allows good material toflow into the passage, runner, gate and mold cavity only;

FIG. 16 shows the nozzle of FIG. 12 in a configuration and position thatshuts off the filling of the passage, runner, gate and mold cavity afterthe mold cavity has been filled;

FIG. 17 shows an alternate bottom fill option for the second embodimentof the present invention where the nozzle plunges from the top side ofthe molding apparatus; and

FIG. 18 illustrates yet another bottom fill option for the secondembodiment of the present invention where the nozzle plunges from thebottom side of the molding apparatus.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

Looking at FIG. 3, a perspective view of a testing apparatus 300 thatemploys a method and apparatus according to one embodiment of thepresent invention can be clearly seen that proves out the invention toform only five spokes as shown and described above with reference toFIGS. 1 and 2. It comprises a platform 302, a central hub 304 that helpsto form the inner annular band that connects the spokes of the tire, asector of a mold 306 that has interarticulating cores for forming theinside surfaces of the spokes, and an annular skirt 308 that forms theouter annular band that also connects the spokes of the tire. Thecentral hub, mold sector and annular skirt are connected to theplatform. A right angle arm 310 is used to attach the mold cores thatextend downwardly for forming the spokes to the platform while the moldcores that extend upwardly are attached directly to the platform 302 asis more clearly seen in FIG. 4. A portion of the valve assembly 312 isalso shown extending from the central huh 304 that selectively opens andcloses a passage that connects the waste reservoir to the runner of thefeed system as will be described further latex. This testing apparatusdoes not spin or rotate, but it is contemplated that it could be used inconjunction with molding or casting equipment that rotates about anyaxis or about multiple axes.

FIG. 4 is a sectional view taken along lines 4-4 of FIG. 3, depictingthe locations of the feed system relative to the cores that form thespokes as well as the cavities that form the inner annular band andouter annular band of the tire. The feed system is shown to have bothtop fill and bottom fill options and it is contemplated that eithercould be used or that both could be used simultaneously or in some sortof timed fashion. The feed system for both the top fill and bottom filloptions comprises two members that are split relative to each other. Thefirst member 314 has as portion of the waste reservoir or channel 318machined into it as well as the runner 320. The second member 316 as theremaining portion of the reservoir 318 machined on it as well as theo-ring or gasket grooves 322 that prevent leaking of the polyurethanebetween theses member. Preferably, the o-ring or gasket grooves aremachined onto the lower member to allow placement of the o-ring orgaskets therein, thereby easing assembly. The feed system furtherincludes a thin gap between the members that serves as the gate 324. Allthe features of the feed system including the waste reservoir, runnerand gate extend substantially around the circular perimeter of the hub,allowing the mold cavity 326 to be filled substantially in an annularfashion as will be better described later. The arrows illustrate thisflow from the runner into the cavity of the mold through the gate.

Turning now to FIG. 5, a perspective sectional view of the first orupper member 314, second or lower member 316 of the feed system, of thebottom, fill option shown in FIG. 4, as well as the valve assembly 312is depicted. The upper member 314 is shown in a translucent state sothat the runner 320 and gate 324 can be seen as dashed lines to extendcompletely around the circular perimeter of half the upper member. Thewaste reservoir 318 can be seen to be a channel that is concentric withthe runner and gate and that is found radially inside of these featuresand does not extend completely around the circular perimeter of theupper member (best seen in FIG. 6). The valve assembly 312 can be seento lie of a conventional plunger design. That is powered by pneumatic orhydraulic means. Alternatively, the valve could be powered by asolenoid. Other types of valves could be used including ball valves orother valves that rotate open and close. It is further contemplated thatthe valve could use some sort of membrane, similar to that shown anddescribed with respect to a feature of the second embodiment of thepresent invention that will be discussed later. The function of thevalve is to open and close the passage 328 from the waste reservoir tothe runner as will be discussed next with respect to FIG. 6.

Focusing now on FIG. 6, it can be seen that this particular valveassembly has as shut off stem 330 that impinges upon the ridge 332 thatseparates the outer o-ring or gasket channel and waste reservoir. Aportion of the shut off stem 330 may also shut off on the o-ring Orgasket itself depending on the design. Furthermore, it can be seen thatthe upper portion of the waste reservoir that is found on the uppermember of the feed system starts a predetermined distance away 334 fromthe valve assembly that opens and closes the passage between the wastereservoir and the runner. Looking at FIGS. 7 and 8, the construction orthe upper and lower members 314, 316 can be seen more clearly that housethe feed system and it can be also seen that the passage 328 that leadsfrom the waste reservoir 318 to the runner 320 has a fan shape. Lookingat FIGS. 6 and 7, the passage is below the top surface 338 of the wastereservoir and is spaced away a predetermined distance S from the surface340 that extends downwardly at a right angle from the top surface. Thesesurfaces act as gas or bubble catchers, helping to prevent trapped airor gas that resulted as the waste reservoir filled from entering thepassage and contaminating the material that flows through runner andwill eventually enter the mold cavity via the gate. Note that only aportion of the aperture 336 that contains the injection nozzle or othermeat is for infecting material into the feed reservoir is shown.

FIG. 9 shows up close the gate and that is has a thickness that funnelsdown to a final thickness T of 0.5 mm and that it curves away from therunner, which is in the upward direction for the bottom fill scenario asillustrated here and in the downward direction for the top fillscenario, into the bottom or top surface respectively of the cavity thatforms the inner annular band of the tire. The stepped split line 346helps center the upper member 314 to the lower member 316 whileorientation holes 348 along with a dowel pin helps establish the properangular orientation between the upper and lower members.

FIGS. 10 and 11 are partial top sectional views showing the feed system,allowing one skilled in the art to see the relative placements of theinjection point 336 for introducing material into the feed system, salve342 for opening and closing the passage 328 found between the wastereservoir 318 and the runner 320, and the an vent 344 located at the endof the waste reservoir. The air vent can comprise any simple valve knownin the art or could also comprise a porous medium that allows air topass through but not the material itself, such as is commonly used inthe injection molding industry. The injection of the material may beaccomplished by using injection nozzles used in the art including thosethat use a compression seal or tapered seal.

Alternatively, the injection nozzle may be of similar construction asthat will be described later with respect to the second embodiment ofthe invention. Various forms of the valve assembly that can be used foropening and closing the passage between the waste reservoir for holdingthe off-ratio material and the runner have already been discussed. It iscontemplated that this valve assembly may be omitted in certain casesprovided that passage way is sized appropriately so that waste materialwill not enter the runner prematurely until good material is introducedinto the starting portion of the waste reservoir. Such a design may beparticularly suitable for top fill situations or other scenarios whereflow back once the mold cavity is filled will not be a problem. In mostcases, it is preferable to have a valve assembly to help ensure poorquality material does not enter the runner and to prevent back flow oncethe mold cavity has been filled.

Now focusing on FIG. 10, the initial filling of the waste reservoir 318is represented by the arrows. First, the material is injected into thewaste reservoir and the air vent 344 is opened. This step may includeopening a valve associated with a nozzle found at the infection point336 and may include previously shutting off the valve 342 locatedbetween the waste reservoir 318 and the runner 320. The materialcontinues to fill the waste reservoir until enough of the material hasfilled the waste reservoir that allows one skilled in the art to beconfident that poor quality material has passed the passage between therunner and the waste reservoir so that it will not enter eventually intothe mold cavity. Once enough initial material has entered into the wastereservoir, the air vent 344 is closed and the 342 valve found betweenthe waste reservoir 318 and the runner 320, if one is present, isopened. This causes a pressure buildup to occur in the waste reservoirso that no more material flows in the waste reservoir and the runnerbegins to fill.

In some cases, the valve 342 between the waste channel 318 and therunner 320 is opened previous to the closing of the air vent 344 and inother cases the air vent lacks a valve and so there is no closing of thevent. It is preferable to open the valve between the waste reservoir andthe charnel before closing the air vent to avoid flow hesitation. Asshown by the terminal point of the arrows, the timing of this is done tohelp ensure that the material does not reach the air vent 344, whichcould potentially foul the vent and prevent it from working in futurecycles of shots of the manufacturing process.

For this embodiment, the timing of filling and stopping the flow ofmaterial into the waste reservoir is achieved by using a timer. Theinventor has calculated the amount of time necessary to fill the wastereservoir with 100 g of material but may vary depending on theapplication. It is contemplated that the timing could be triggered byusing other means known in the art including pressure switches,temperature sensors, and capacitance sensors. Regarding the use oftemperature sensors, the inventor notes that the typical moldtemperature is 100 C and the temperature of the polyurethane 80 C. So,if the sensor is initially detecting the air temperature, then anincrease in temperature may be used to shut off the air vent valveand/or to open the valve that allows material to flow into the runner.On the other hand, if the sensor is initially detecting the moldtemperature, then a decrease in temperature may be used to shut off theair vent valve and/or to open the valve that allows material to flowinto the runner.

Turning now to FIG. 11, the process of filling the runner 320, gate 324and subsequently, the mold cavity is illustrated. After the valve 342 isopened leading to the runner 320 and the an vent 344 is closed, goodmaterial flows into the runner completely along its circular peripheryas hydrostatic pressure (represented by the cross-hatched area in FIG.11) causes material to no longer flow pass the passage 328. As the gateis greatly restricted compared to the runner, little to no materialflows into the cavity until the entire limner is filled, at which pointthe material will flow into the cavity in essentially an annular fashionalong the entire circumference of the tire. After the material in themold cavity, gate, runner, passage and waste reservoir 318 has beencured or hardened, the tire and attached feed system are removed fromthe molding apparatus were the gate is trimmed so that the feed systemis detached from the tire. For the testing apparatus, this needs to bedone manually, however, it is contemplated that the members that formthe feed system would be opened automatically and the part and feedsystem would be removed or ejected automatically as is commonly done inthe injection molding industry so that the process could be done withoutmanual intervention. At approximately the same time, the nozzle thatinjects the material into the feed system would be flushed with solventover a drum to get it ready for the next cycle or shot.

Adjustments may be made to this embodiment of the invention depending,on the application. For instance, the length, placement, size andconfiguration including the flow paths as well as cross-sectional shapesof the gate, runner, waste reservoir and passage between the wastereservoir and the runner may be adjusted as desired as well as how theyare defined or machined into structural members that house the void thatto ms the feed system. Likewise, the relevant placement of thesefeatures to each other as well as in what structural members they arelocated may be modified. In most cases, the passage between the runnerand waste reservoir is located closer to the injection point than to theend of the waste reservoir. In fact, in most applications the lineardistance from the passage to the end of the waste reservoir, which issere the air vent is typically found, is at least twice the lineardistance from the injection point to the passage along the flow path,allowing a significant material to be held in the waste reservoir tohelp ensure, poor quality material does not make it into the runner andlater into the mold cavity via the gate. Similarly, the runner, gate andwaste reservoir do not need to have curved flow paths but may be altereddepending on the application or shape of the article to be manufacturedand could be straight or flow along any desired flow path.

It is father contemplated that a shut off valve may be used that islocated just past the passage along the flow path of the waste reservoirto shut off the flow to the waste reservoir one the bad material haspassed the passage. In such a case, the shut off valve that isoperatively associated with the an vent that is in fluid communicationwith the waste reservoir may be unnecessary.

FIG. 12 shows a molding apparatus 400 according to a second embodimentof the present invention. The apparatus includes a two piece injectionnozzle 446, which is capable of plunging back and forth in the verticaldirection and that is inserted into the apparatus via an injection point436, as waste reservoir 418 that is located concentrically around thenozzle and above the central hub 404 (shown in FIG. 13) and mold cavity426 (also shown in FIG. 13), a ramped valve member 442, and a membrane448 that is made of a cured material that is compatible with thepolyurethane used to mold the tire and may be made of the same material.The thickness of the membrane may be 2.6 mm but may vary depending onthe application. The membrane is attached to the curved surface of theramped valve member 442 and to the curved surface of the lower may be416 using a primer for attaching the polyurethane to metal, creating adiaphragm typo valve that can move up and down with the ramped valvemember (see positions of the valve member 442 and membrane 448 in closedposition shown in solid lines while the open position is shown inphantom lines using reference numerals 442′ and 448′) while preventingthe liquid polyurethane from seeping into seams of the apparatus andfouling the equipment, which is difficult to do using traditional sealsor gaskets.

A compression spring (not shown) biases the valve member so that its topshut off surface 454 seals against the upper member 414, effectivelyclosing the gate 424 from the runner 420. Of course, the runner becomeslarger when the valve member 442 is lowered as will be described butthere is always a gap between the valve member and the upper member tohelp ensure the top surface of the valve member 442 shuts of on theupper member 414 that. This spring force may be counteracted toeffectuate opening of the valve as will be described. The runnerthickness may vary but the inventor has found thicknesses such as 0.5 mmto 1 mm to be suitable depending on the application. Of course, the gatereduces in size to restrict flow into the cavity.

Looking now at FIG. 13, the two piece nozzle 446 comprises a slidinginner member 450 and outer sleeve 452 that is also able to translateindependently of the inner member. The first step in the process forthis embodiment for filling the mold cavity 426 is for the outer sleevemember 452 to move upward while the inner member 450 is flush with theopening to the passage 428 that connects the waste reservoir 418 to therunner 420, creating an annular opening from the nozzle 446 into thewaste reservoir while also blocking any flow into the runner. Thisallows the poor quality material to fill the basin of the wastereservoir as air vents 444 are provided to allow the displacement ofair. This continues until a predetermined amount of material has beeninjected into the waste reservoir. This can be accomplished usingtimers, pressure switches, capacitance switches, or temperature sensorsthat are placed at strategic heights in the waste reservoir, similar towhat has already been described for the first embodiment. The inventorrefers to this step as partial nozzle insertion for the diversion ofmaterial flow into the waste reservoir. The movement of the nozzle canbe effected by means commonly known in the art including pneumatic,hydraulic, solenoids, etc.

It is contemplated that in order to achieve independent motion of theouter sleeve 452 and inner member 430 of the nozzle, an alternateconfiguration shown in phantom lines 452′ and 450′ in FIG. 13 might beused where the back stein portion extends through the top surface of theelbow portion of the outer sleeve and the relative movement of eachcomponent may be achieved using means known in the art including rackand pinion, hydraulic, pneumatic and solenoid means. In addition, othermeans in the art known for moving shutoff pins in the molding industrymight be employed including the use of guide members for guiding themovement of the pin that have orifices arranged around the periphery ofthe guide members for allowing fluid to pass by the guide members.

As shown by FIG. 14, once enough material has been diverted into thewaste reservoir 418, both the inner member 450 and outer sleeve 452 ofthe nozzle 446 are moved vertically until the annular opening betweenthe waste reservoir and the nozzle is reduced, beginning to pinch offthe flow of material into the waste reservoir. At the same time, theinner member 450 of the nozzle pushes down on the valve member 442,overcoming the spring force that biases the valve member closed,resulting in an annular opening between the passage 428 and the nozzle446, which allows material to start to flow into the runner 420. Thetiming of movement of the various its of the nozzle and valve memberhelp to prevent the formation of bubbles in the material as well asavoid any flow hesitation.

Next as shown by FIG. 15, the outer sleeve 452 and inner member 450 ofthe nozzle are advanced to the furthest extent into the apparatus 400,causing the outer sleeve 452 to shut off all flow into the wastereservoir 418 while creating a large annular opening from the nozzle 446to the passage 428 and runner system 420. The runner would naturallyfill in a concentric fashion and would feed the concentrically shapedgate in the same manner, allowing the filling of the spokes and annularbands (designated as mold cavity 426) of the tire symmetrically andconsistently. As can be seen, the two piece nozzle and the relativemovements of the inner member and outer sleeve allow it to act as a shutoff valve that can stop flow into the waste reservoir while also actingas a shut off valve that can open and close the passage to the runner inconjunction with the ramped valve member.

As illustrated by FIG. 16, at the end of the mold fill, the flow ofmaterial is stopped by retracting completely the inner member 450 of theof the nozzle 446 to its seated position on the outer sleeve 452, whichin turn allows the valve member 442 to close due to the biasing of thespring force, sealing the passage 428 from the runner 420. At the sametime, the position of the outer sleeve 452 of the nozzle 446 may remainthe same to prevent bad material from leaving the waste reservoir 41 andentering back into the passage 428.

At approximately the same time or slightly after the valve member shutsoff the passage from the waste reservoir to the runner, the nozzle isshut off as the inner member impinges upon the outer sleeve. Also, themembrane forces some remaining material from the manner through the gateinto the cavity, reducing the amount of waste material. Before thematerial is cured, the nozzle may be flushed with solvent to ready itfor the next cycle or shot, material found in the waste reservoir thenneeds to be removed manually. Likewise, the material found in the gateresembles an umbrella that extends radially inward along thecircumference of the inner annular band of the tire and needs to betrimmed from the tire. It is contemplated that this apparatus could beautomated so that the tire as well as the feed system after each cycleor shot could be removed or ejected automatically.

For this embodiment, the material found in the waste reservoir and gateas well as the tire itself could be extricated from each other and theapparatus in a manner similar to that used in a conventional three platestyle mold used in the injection molding industry. As with the previousembodiment, the configuration, sizing and relative placement of thevarious voids to each other as well as the type of nozzle, such as itsconstruction, whether single piece or multi-piece, as well as the timingof the filling steps and ways of accomplishing them may be modified tosuit the application. For example, it is contemplated that a singlepiece nozzle that plunges could be used to first fill the wastereservoir before a valve is opened to allow material to fill the runner,gate and mold cavity.

FIG. 17 shows a bottom fill version fu this embodiment and worksessentially the same way except with the nozzle 446 plunges from abovethe molding apparatus 400. All other components as well as the movementsthe nozzle 446 and its various parts work the same. The essentialdifference is that the runner 420 curves upward into the gate 424 andthat the placement and configuration of the waste reservoir 418 ischanged such that it is located mar the bottom of the molding cavity426. On the ether hand, FIG. 18 depicts a bottom fill version for thesecond embodiment that is essentially the same as FIG. 17 except thatthe nozzle 446 plunges in the upward vertical direction to effectuateopening of the valve member 442 and the components of the nozzle 446,ramped valve member 442 and membrane 448 have an orientation that isrotated 180 degrees about a horizontal axis as compared to any of theother versions of the second embodiment discussed thus far. Also, anadditional component that acts as the basin 456 for holding wastematerial is provided that is found below the molding cavity 426.

For any of the embodiments, it is further contemplated that the nozzlecould have the ability to plunge but that the inner member and outersleeve would not have the ability to translate relative to each other aswould be the case when the inner member is press fit into the outersleeve. In such a case, more turbulence in the flow might be created asthe flow to the waste reservoir is pinched off and the now to the runneris increased. Also, some slight dripping make occur when moving thenozzle to a drum to be flushed between molding cycles. In other words,the term plunging nozzle means that the outside housing of the nozzle iscapable of moving along an axis so that fluid communication may beestablished between the nozzle and one or more voids of the feed system.

While only a tread that is formed with spokes that is part of anon-pnuematic tire has been specifically described herein, it iscontemplated that this process could be used with tires that use a gasalong with spokes (often referred to as a hybrid tire) to support theload applied to the tire. The tire does not need to be configured with ashear layer or have other properties or features as the tire containedin U.S. Pat. No. 7,201,194. Also, other materials may be used instead ofpolyurethane such as any thermosetting material that is suitably durableand strong to support the loads applied to the tire. Furthermore, theembodiments discussed herein focused on adding spokes to the tire butthe present invention is also applicable to forming other regions of atire. Testing of both embodiments has indicated that both solutions aresuitable to provide good quality material to the mold cavity withoutintroducing poor quality material to a reasonable degree.

While this invention has been described with reference to particularembodiments thereof, it shall be understood that such description is byway of illustration and not by way of limitation. For example, avertical molding press has been described but it is contemplated that ahorizontal molding press could also be used. In like fashion, the moldhas been described as having a cylindrical shape, but it could haveother shapes such as a square or rectangular cube. Also, this inventioncould be used on other articles of manufacture in addition to tires andthese articles could have shapes other than cylindrical or circular.Furthermore, the dimensions and configurations of the features of theembodiments of the present invention may be modified or optimized tosuit the application.

Finally, different aspects and features of some of the embodimentsdiscussed herein may be substituted for other features of otherembodiments to yield further embodiments as has been already mentioned.Accordingly, the scope and content of the invention are to be definedonly by the terms of the appended claims.

What is claimed is:
 1. An apparatus for molding or casting an article ofmanufacture having a mold cavity and a feed system for filling the moldcavity with a fluid material, said feed system comprising: a nozzle thatdefines a plunge axis and that is configured for plunging along theplunge axis a valve member actuating by the plunge nozzle along theplunge axis, and structural members that define a series of voidsincluding a waste reservoir, a runner, a passage that connects the wastereservoir to the runner, allowing fluid communication between the wastereservoir and the runner, an injection point for introducing fluid intothe waste reservoir, and a gate that provides fluid communicationbetween the runner and the mold cavity, and wherein the waste reservoiris immediately adjacent the injection point along the plunge axis, thepassage is further away from the injection point than the wastereservoir and is immediately adjacent the waste reservoir along theplunge axis, the runner is further away from the injection point thanthe passage and is immediately adjacent the passage along the plungeaxis, the gate is further away from the injection point than the runnerand is immediately adjacent the runner along the plunge axis, and themold cavity is furthest away from the injection point than any othervoid along the plunge axis.
 2. The apparatus of claim 1, wherein theinjection point houses said nozzle that has a plunge axis and thatplunges along the axis.
 3. The apparatus of claim 1, which furthercomprises an air vent that is in fluid communication with the wastereservoir.
 4. The apparatus of claim 1, which further comprise a shutoff valve that is operatively associated with the passage for openingand closing the passage.
 5. The apparatus of claim 3, wherein the airvent includes a shut off valve.
 6. The apparatus of claim 1, wherein thewaste reservoir has a volume, the runner has a volume, the passage has avolume and the mold cavity has a volume, wherein the passage has asmaller void volume than the runner or waste reservoir.
 7. The apparatusof claim 6, wherein the void volume of the waste reservoir is greaterthan the void volume of the passage or the runner.
 8. The apparatus ofclaim 2, wherein the nozzle comprises two pieces including an innermember and an outer sleeve, which are configured for independentlytranslating relative to each other.
 9. The apparatus of claim 8, whereinthe pieces of the nozzle are attached to each other with the innermember having a stem and the outer sleeve having a right elbow with atop surface and the stem of the inner member extends thru the topsurface of the right elbow.
 10. A method for manufacturing an articlecomprising: providing an apparatus with structural members that definevoids including a mold cavity, a feed system that includes an injectionpoint, waste reservoir, a runner, a passage that connects the wastereservoir to the runner, a gate that connects the runner to the moldcavity, and a nozzle with a plunge axis along which the nozzle plunges,wherein the injection point, waste reservoir, passage, runner, gate andmold cavity are positioned sequentially along the plunge axis in anyorder; moving at least a portion of the nozzle to a position along theplunge axis where the nozzle begins filling the waste reservoir; movingat least a portion of the nozzle to another position along the plungeaxis where it begins filling the passage and runner; providing a shutoff valve which is operatively associated with the passage for openingand closing the passage; wherein said providing a shut off valveincludes providing a ramped valve member; injecting fluid material intothe waste reservoir; and stopping the filling of the waste reservoir.11. The method of claim 10, which further comprises generating a signalthat indicates when the waste reservoir has been partially filled. 12.The method of claim 10, wherein providing the nozzle includes providingthe nozzle with a two piece construction including an outer sleeve andan inner member that are configured for translating relative to eachother.
 13. The method of claim 10, which further comprises opening thevalve that is operatively associated with the passage for allowing fluidcommunication between the waste reservoir and the runner.
 14. The methodof claim 12, wherein said moving at least a portion of the nozzle tofill the waste reservoir includes moving the outer sleeve.
 15. Themethod of claim 12, wherein said moving a portion of the nozzle to fillthe passage and runner includes moving the inner member of the nozzle.16. The method of claim 10, which further comprises biasing the rampedvalve member in a closed position.